On the next to last day of the 1957 season in the second to final game in Brooklyn Dodgers history, Valdez made the start for the team in Philadelphia. For "El Latigo"
(the "Whip") it would be his only start in the majors. The Dodgers staked him to an early 8-1 lead, but he wasn't able to get out of the fifth inning and was relieved by Ed Roebuck, who was credited with an eventual 8-4 victory. Rene did win a game and also lost one in four relief appearances for the Dodgers. He finished out at 1-1 with a 5.54 ERA in his only year in the big leagues.

Valdez would spend until 1960 with the Montreal Royals of the AAA
International League, winning 15 games for the pennant winning 1958 team. He wound up up having two winning years and two losing and
would then spend 1961 with the Spokane Indians of the Pacific Coast League going 14-11 with a 3.64 ERA. Rene finished out the balance of his pro baseball career with three years (1962-64) in the Mexican Leagues winding up with a 152-111 record and a 3.60 ERA while pitching 2,095 innings.

A player under the name "Rene Gutierrez" pitched in the Cuban leagues in the 1950s, including for the Almendares.